Cuban Rusney Castillo arrives safely at third base at the XVI Panamerican Games in 2011. / Raul Arboleda, AFP/Getty Images

by Bob Nightengale, USA TODAY Sports

by Bob Nightengale, USA TODAY Sports

The Boston Red Sox have agreed in principal to sign Cuban defector Rusney Castillo to a six-year, $72.5 million contract Friday, the richest by any defector in baseball history, according to an official with direct knowledge of the negotiations told USA TODAY Sports.

The official spoke only on the condition of anonymity since the deal has yet to become official. Castillo is scheduled to undergo his physical Saturday.

Castillo, 27, who is represented by Jay Z's Roc Nation Sports, a joint venture with CAA Baseball, will join the Red Sox this season. He will be paid $72 million over six years beginning in 2015.

The contract will be heavily backloaded, the official said, assuring that the Red Sox will not go over the $189 million luxury tax. The Red Sox's current 40-man payroll is $166.6 million, according to contract information obtained by USA TODAY Sports.

The Red Sox out-bid the Detroit Tigers for the speedy outfielder. The Tigers were hoping to use Castillo to replace recently traded center fielder Austin Jackson.

The Red Sox plan to use Castillo, 5-foot-9, 185 pounds, as a speedy leadoff hitter. His power and speed combination has drawn comparisons to Pittsburgh Pirates center fielder Andrew McCutchen.

Castillo, a right-handed hitter, was Cuba's national team's center fielder in the 2011 World Cup in Panama, hitting .512 with two homers, two triples and four doubles in the 10 games, including a .524 on-base percentage and .854 slugging percentage.